Well here goes:

lookup:
db 01h, 02h, 04h, 08h, 10h, 20h, 40h, 80h

mov dptr,#lookup
mov a,P0
anl a,#7H
movc a,@a+dptr
jb P0.3,setp2
mov P1,a
sjmp done
setp2:
mov P2,a
done:
...

Thats 8 instructions and 8 bytes lookup. It may be possible to make it 1 instruction shorter by using the movc a,@a+pc instruction.

Mike Karas